It is common to employ a plurality of cylindrical side brushes having substantially vertical axes of rotation in an automatic car washing apparatus. Such brushes are typically mounted for pivotal displacement toward and away from a vehicle wash lane so as to contact at least the side surfaces of the vehicle as it progresses past the brushes.
One of the problems associated with the use of such vertically oriented brushes is the fact that the direction of tangential motion of the rotating brush bristles relative to the side of the vehicle is substantially horizontal. Accordingly, the brush bristles can damage or dislocate vehicular appendages, such as radio antennas and side mounted rear view mirrors. In addition, such vertically oriented side brushes are in scrubbing contact with any given area of the vehicle side surface for only a brief instant and, accordingly, the thoroughness of such scrubbing is occasionally less than adequate, particularly after the brush bristles have become partially worn or if the vehicle surface is characterized by one or more vertical surface discontinuities or contouring.
Also, while it has been recognized that to maximize the scrubbing effectiveness of the brushes it is desirable to rotate the same against the movement of the vehicle in the wash line, if the brushes were inclined towards the vehicle as is the standard practice, the tangential movement would be downward with respect to the vehicle antenna, producing a buckling deflection of the antenna tending to cause breakage thereof, even if the brushes were inclined at a long shallow angle so as to minimize side forces on the antenna as is taught by the present invention.